Electrical heating apparatus



2 Sheets-Sheet 1 g llllllllllllllllllllllllllllllllllllllll llllllllllllllll l I g MM A T a N 0 N n 2 mm m 2 9 A 5 a 7 5 J W 6 W m M J. C. M DONALD ELECTRICAL HEATING APPARATUS Filed May 16, 1934 r I k/ J W 1 2 7g 75 w Feb. 5, 1935.

Feb. 5, 1935 J. c. MCDONALD I ELECTRICAL HEATING APPARATUS 2 Sheets-Sheet 2 Filed May 16, 1954 Z/l/I/l/l/l/l /l7///////////////////l 71/! 5: VII

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6. A TTORNEY Patented Feb. 5, 1935 UNITED STATES PATENT OFFICE John C. McDonald, New York, N. Y., assignor of one-half to Edward L. Corbett, New York, N. Y.

Application May 16, 1934, Serial No. 725,983

11 Claims.

My invention relates broadly to electric heaters and more particularly to an electric heater for fluids in which the heater has a high degree of thermal and electrical efliciency, producing large heating properties for small power consumption.

One of the objects of my invention is to provide the construction of an electric heater in which all heat losses, core losses, copper losses, and secondary losses accompanied by heat are utilized to directly heat a fluid for thus utilizing the thermal effects of losses which heretofore have detracted from electrical and thermal efficiency.

Another object of my invention is to provide the construction of an electric heater in which fluid to be heated is circulated about the core structure of the transformer and in direct contact with secondary members which are inductively excited from a primary system supported by the core structure of the transformer.

Still another object of my invention is to provide a construction of electrical heater in which the effective number of turns of the primary winding may be readily selected through a tap changing system for controlling the ratio of transformation in the heater.

A further object of my invention is to provide a construction of electric heater in which a tubular conduit is wound on opposite portions of a closed magnetic core structure to provide a fluidtight housing for a multiplicity of turns of a primary winding while permitting the primary system to operate in a submerged fluid-tight tank for inductively exciting a multiplicity of closed secondary turns directly submerged in the fluid to be heated.

A still further object of my invention is to provide a construction of electric heater comprising a closed magnetic core providing supports for separate metallic conduits coiled on opposite portions of the magnetic core structure and providing fluid-tight housings for a multiplicity of primary wire turns, said conduits being inductively related to a multiplicity of shunt circuit secondary members with means for cross-bonding the separate conduits for eliminating detrimental efiects of closed magnetic fields.

Other and further objects of my invention reside in the construction of electric heating apparatus, as set forth more fully in the specification hereinafter following by reference to the accompanying drawings, in which:

Figure 1 is an elevational view of the transformer system with the fluid containing tank illustrated in cross-section; Fig. 2 is a plan view of the electric heating apparatus shown in Fig. 1; Fig. 3 is a cross-sectional View taken through the terminal box of the transformer system on line 3'-3 of Fig. 4; Fig. 4 is a vertical sectional view taken through the electric heating apparatus on line 44 of Fig. 2, the view being shown on an enlarged scale; Fig. 5 is a horizontal sectional view taken through the heating apparatus on line 55 of Fig. 4; Fig. 6 is a vertical sectional view taken through the terminal box on line 66 of Fig. 2; Fig. '7 is a vertical cross-sectional view taken through the terminal box on line 7-7 of Fig. 2 and illustrating the manner of effecting the change in ratio of the primary system with respect to the secondary system; and Fig. 8 is a cross-sectional View taken through the conduit forming a fluid-tight housing for the primary system.

Referring to the drawings in detail, reference character 1 designates the fluid-tight tank in which the transformer system is submerged. The fluid inlet to tank 1 is shown at 2 controlled by a suitable valve 3. The fluid outlet for the heated fluid is shown at 4 controlled by valve 5. The tank 1 is constructed in approved form with fluid-tight riveted joints at 6 and 7, respectively, connecting the bottom 8 and top 9 with the tank 1. The tank 1 serves as a support for the closed magnetic core structure indicated at 10, which core structure is mounted on insulated pedestal members indicated at 11 resting on the bottom 8 of the container 1. It will be noted that the upwardly projecting side portions a and 10b of the magnetic core structure 10 are provided with interlocking lugs or tongues 10a and 10b which fit in coacting grooves 12a and 12b in the horizontally extending core section 12. In the assembly process, the transformer is first mounted in the container 1 when the container is in inverted position. In mounting the horizontallyextending portion 12 of the core structure an insulated strip 14 is laid against the head 9. The core structure with the assembled windings and coils thereon, as will be hereinafter described, is then assembled in position by the interlocking of tongues 10a and 10b with grooves 12a and 12b. The insulated pedestals 11 are placed in position and the bottom 8 riveted in position by means of the rivets illustrated at 6 for providing a fluid-tight container entirely enclosing the transformer structure.

Prior to the assembly process, the core structure 10 with its upstanding side portions 10a and 10b have the windings entirely assembled thereon. The primary winding is housed within a "conduits l5 and 16 returning to terminal post and l6- o f the conduit returning to terminal post 37, 39, 4143, 45, 47,49, 51', 53 and 55. The oppair of conduits 15 and 16 of high magnetic permeability material. The conduits 15 and 16 are electrically conductive but are insulated end to end by means of an insulated coupling 17 and insulated from the container 1 and terminal box 22 and from the closed magnetic core structure. The insulation of the conduits from the closed magnetic core structure is cheated by providing insulated sleeves 96 and 97 on the portions 19a and 10b of the core, respectively. The insulation of the conduits from the container 1 and terminal box 22 is effected by means of insulated sleeves 20 and 21. The insulated sleeves 96 and 97 wholly cover the opposite portions 10a and 10b of the core and preclude direct electrical contact between the conduit and'the; core structure. The opposite ends of the conductive conduits15 and 16 are electrically cross-bonded by means of electrical bonds shown at 18 and 19. Each of the conduits 15 and 16 are wound in the shape of inductances and embrace the portions 10a and 10b of the magnetic core structure. The conduits form a closed fluid-tight'housing for the turns of the primary winding. The ends of the conduits 15and 16 project vertically through the upper head 9 oi the fluid-tight container.

The end of the, conduit 15 projects through insulated sleeve or bushing 20. The end of the conduit 16 projects through insulated sleeve or bushing 21. The terminal box 22 is supported by the respective insulated sleeves or bushings 20 and 21 or by other'suitable means through the nuts 20a and 21a engaging the insulated bushings20 and 21, as shown. The primary system comprises the conductor 23 which passes through a bushing in the closure 24 of terminal box 22 and connects to terminal 25 mounted on terminal board 26. The terminal board 26 is constructed of appropriate insulation material and is mounted by suitable securing means on inwardly projecting horizontallyextending flange 22a. of the terminal box 22. Terminal 25 is bonded beneath terminal board 26 to conductor 27 which passes entirely through the separate 28 adjacent the opposite edge of theterminal board 26. Terminal 28 is connected by bus 29 with terminal, 30. The second primary turn extends from terminal 38 through the sections 15 31*adjacent the opposite edge of. the terminal board 26; Similarly, terminal 31 is connected to terminal 32through cross-condu'ctor'33 on the terminal board 26. This same staggered connection iscarried out for allof the turns of the primary system. That is tosay, the successive turns of the primary winding are bonded to terminal posts 28, 31, as described and the successive turns bonded to terminal posts 33, 35,

These terminal posts are cross-bonded in staggered relation by busses56, 58, 59, 60, 61, 62, 63,

64, 65, 66 and 67, as indicated. The terminal connection for the primary system is shown at 69 passing through a bushing in the insulated closure 24 and connected with terminal post 70 from which'fiexible lead71 extends with a pin terminal 72 on the end thereof. The closure 24 carries a multiplicity of socket members. 73, 74, 75, 76, 77, 78 and.79 which depend downwardlyv and provide slip. connections with up-.

wardly projecting pins 86, 81, 82, 83, 84, 85 and 86 carried by terminals 55, 53, 51, 49, 47, 45 and 13, respectively. This arrangement provides means whereby the closure 24 may be engaged or disengaged with respect to the terminal box 22 and connections automatically established with the ends of certain of the primary turns. By changing the connection of the pin terminal in any one of the several sockets, the effective number of primary turns may be selected for thus changing the transformation ratio of the transformer in accordance with heating requirements. That is to say, the primary winding may be varied by single turns to secure the effective number of primary turns in the primary circuit as may be required.

The general arrangement of the multiplicity of primary conductors within the fluid-tight conduit is shown in Fig. 8 where the several insulated conductors are represented by reference character .87.

V The conduitsl and 16 areeach surrounded by insulated tubes shown at 88 and 89. Thesetubes are suitably slotted at88a and 89a to allow the passage of conduits 15 and 16 laterally to the in?- terconnecting position provided by coupling 17.

The insulated tubes 88 and 89 provide supports.

for a plurality or shunt ring members which are positively spaced apart by annular sleeves en.-.

gaging the cylindrical tubes. Cylindrical tube 88 provides a support for secondary ring members 90 whichare positively spaced by annular.

members 91 disposed'therebetween. Cylindrical tube 89 provides a support for a plurality of ring members 92 which are positively spaced by annular ring members 93.

The apparatus of my invention has been found to be highly eiiicient in operation. The secondary rings 90 and 92 are heated by secondary currents and eddy currents resulting .from voltages induced therein by the primary system and, impart such heat directly to the fluid 95 which is circulated through the tank 1. The h at normally generated in the magnetic core structure is also imparted to the fluid. Certain heating effects which are obtained in'the sections of metallic conduits 15 and 16 are also liberated to the fluid.

. The cross-bonding of the sections 15 and '16 serves efiiciency of the system. The high magnetic permeability of thesections 15 and 16 avoids any a substantial magnetic losses and yet insures, the fluid-tight enclosure of the primary system. The means for selecting the efiective number of primaryturns may be adjusted with all necessary accuracy to obtain the required heating efiects. Automatic thermostatic control may be applied to the apparatus of my invention.

In lieu of the metallic pipe system which I have represented at 15 and 16 and the special iormof insulation shown at 17, I may employa pipe of insulation material and thereby avoid the necessity of insulation of the pipe sections with respect to each other and insulation of the pipe sections with-respect to the magnetic'core 10 and with respect to the casing 1 and terminal b X 22.

It will be understood that the primary winding may be calculated as the product of the effective number of turns of the conduits 15 and 16 on the closed magnetic core 10 and the number 0 wires within the conduits.

The heating elements comprising the several shunt secondary elements 90 and 92 which are separatelyinductively coupled to the primarysyse t'em, are heated in proportion-to the transfor-' mation ratio secured by selecting the number of primary wire turns in the conduits which house the primary winding.

The tap changing or terminal box 22 also acts as a power factor corrector for the transformer unit. When one wire is disconnected, eight turns are dropped from the primary winding. This decreases the ratio of transformation thereby reducing the voltage on the inductive secondary circuits. Due to the decrease in the primary resistance, however, more current is drawn through the primary circuit. 1200 circular mils per ampere must be provided in the primary conductor to get a high power factor. So, if the primary wire is overloaded so that 1200 circular mils per ampere of primary current is not provided, there will be a lower power factor. It is then readily seen that by the tap changer, any given ampere load, in amperes, can be produced by adding or dropping out wires in the connection box.

I realize that many modifications may be made in the structural arrangement of parts of the apparatus and I intend no limitations upon my invention other than are imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. In an electric heater, a fluid-tight casing,

a closed magnetic core supported in said fluidtight casing, a pair of conduits of high magnetic permeability, a multiplicity of wire turns constituting the primary winding enclosed in said conduits, means supporting said conduits on opposite portions of said closed magnetic core, and a multiplicity of shunt circuit secondary turns mounted in inductive relation to said primary winding and directly exposed to the circulation of fluid in said fluid-tight casing.

2. In an electric heater, a fluid-tight casing, a closed magnetic core supported in said fluid-tight casing, a pair of conduits of high magnetic permeability, a multiplicity of wire turns constituting the primary winding enclosed in said conduits, means supporting said conduits on opposite portions of said closed magnetic core, a multiplicity of shunt circuit secondary turns mounted in inductive relation to said primary winding and directly exposed to the circulation of fluid in said fluid-tight casing and means for controlling the transformation ratio between said primary winding and said secondary turns.

3. In an electric heater, a fluid-tight casing, a closed magnetic core supported in said fluidtight casing, a pair of conduits of high magnetic permeability, a multiplicity of wire turns constituting the primary winding enclosed in said conduits, means supporting said conduits on op posite portions of said closed magnetic core, a multiplicity of shunt circuit secondary turns mounted in inductive relation to said primary winding and directly exposed to the circulation of fluid in said fluid-tight casing, and switching means connected with the wire turns of said primary winding for controlling the number of said wire turns effective with respect to said secondary turns.

4. In an electric heater, a fluid-tight casing, a closed magnetic core supported in said fluid-tight casing, a pair of conduits of high magnetic permeability, a multiplicity of wire turns constituting the primary winding enclosed in said conduits, means supporting said conduits on opposite portions of said closed magnetic core, a multiplicity of shunt circuit secondary turns mounted in inductive relation to said primary winding and directly exposed to the circulation of fluid in said fluid-tight casing and means for electrically insulating said conduits from said casing.

5. In an electric heater, a fluid-tight casing, a closed magnetic core supported in said fluid-tight casing, a pair of conduits of high magnetic permeability, a multiplicity of wire turns constituting the primary winding enclosed in said conduits, means supporting said conduits on opposite portions of said closed magnetic core, a multiplicity of shunt circuit secondary turns mounted in inductive relation to said primary winding and directly exposed to the circulation of fluid in said fluid-tight casing, means for electrically insulating said conduits from said casing and separate means for cross-bonding each of said conduits for neutralizing electromotive forces induced in each of said conduits.

6. In an electric heater, a fluid-tight casing, a closed magnetic core supported in said fluidtight casing, a pair of conduits of high magnetic permeability, a multiplicity of Wire turns constituting the primary winding enclosed in said conduits, means supporting said conduits on opposite portions of said closed magnetic core, a multiplicity of shunt circuit secondary turns mounted in inductive relation to said primary winding and directly exposed to the circulation of fluid in said fluid-tight casing, means for electrically insulating said conduits from said casing and means for electrically insulating said conduits from said closed magnetic core.

7. In an electric heater, a fluid-tight casing, a closed magnetic core supported in said fluid-tight casing, a pair of conduits of high magnetic permeability, a multiplicity of wire turns constituting the primary winding enclosed in said conduits, means supporting said conduits on opposite portions of said closed magnetic core, a multiplicity of shunt circuit secondary turns mounted in inductive relation to said primary Winding and directly exposed to the circulation of fluid in said fluid-tight casing, means for electrically insulating said conduits from said casing, means for electrically insulating said conduits from said closed magnetic core and means for electrically cross-bonding said conduits for neutralizing electromotive forces induced in each of said conduits.

8. In an electric heater, a fluid-tight casing, a closed magnetic core supported in said fluid-tight casing, a pair of conduits of high magnetic permeability, a multiplicity of wire turns constituting the primary winding enclosed in said conduits, means supporting said conduits on opposite portions of said closed magnetic core, insulated tubes extending over the coiled turns of said conduits and shunt circuit secondary turns mounted on each of said insulated tubes.

9. In an electric heater, a fluid-tight casing, a closed magnetic core supported in said fluid-tight casing, a pair of conduits of high magnetic permeability, a multiplicity of wire turns constituting the primary winding enclosed in said conduits, means supporting said conduits on opposite portions of said closed magnetic core, insulated tubes extending over the coiled turns of said conduits, shunt circuit secondary turns mounted on each of said insulated tubes, and means carried by said insulated tubes for positively spacing said shunt circuit secondary turns in predetermined spaced relation.

10. In an electric heater, a fluid-tight casing, a closed magnetic core supported in said fluid-tight casing, a pipe system having a multiplicity of turnswrappedbn opposite portionsiof said closed? magnetic core, a primary winding threaded through said pipesystem,-:a multiplicity of :shunt ring members inductively coupled to'said primary winding, and means for selectively connecting the effective number of turns of said primary winding.

11. In an electric heater, a fiuid-tightcasing, a

closedmagnetiocore supported in said fluid-tight casing, a pipe system having av multiplicity of turns wrapped on opposite portions of said closed magnetic corey a primary winding threaded through said pipe system, a multiplicity of "shunt with said closed magnetic core and 'with said mu1-- tiplicity of :shunt rings for extracting heat therefrom.

JOHN C. MCDONALD. 10' 

